title: Multifocal branch-duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas: magnetic resonance (MR) imaging pattern and evolution over time.
abstract: OBJECTIVE
  The aim of our study was to follow the evolution over time of multifocal intraductal papillary mucinous neoplasms (IPMN) of the pancreatic duct side branches by means of magnetic resonance imaging (MRI).
  
  
  METHODS
  A total of 155 patients with multifocal IPMN of the side branches were examined with MRI and MR cholangiopancreatography (MRI/MRCP). Inclusion criteria were patients with ≥2 dilated side branches involving any site of the parenchyma; presence of communication with the main pancreatic duct and previous investigations by MRI/MRCP within at least six months. Median follow-up was 25.8 months (range, 12-217). Patients with a follow-up period shorter than 12 months (n=33) and those with a diagnosis of multifocal IPMN of the side branches without any follow-up (n=14) were excluded from the study. The final study population thus comprised 108 patients. A double, quantitative and qualitative, analysis was carried out. The quantitative image analysis included: number of dilated side branches in the head-uncinate process and body-tail; maximum diameter of lesions in the head-uncinate process; maximum diameter in the body-tail; maximum diameter of the main pancreatic duct in the head and body-tail. The qualitative image analysis included: presence of malformations or anatomical variants of the pancreatic ductal system; site of the lesions (head-uncinate process, body-tail, ubiquitous, bridge morphology); presence of gravity-dependent intraluminal filling defects; presence of enhancing mural nodules.
  
  
  RESULTS
  At diagnosis, the mean number of cystic lesions of the side branches was 7.09. The mean diameter of the cystic lesions was 13.7 mm. The mean diameter of the main pancreatic duct was 3.6 mm. At follow-up, the mean number of cystic lesions was 7.76. The mean diameter of the cystic lesions was 13.9 mm. The mean diameter of the main pancreatic duct was 3.7 mm. Intraluminal filling defects in the side branches were seen in 18/108 patients (16.6%); enhancing mural nodules were seen in 3/108 patients (2.7%).
  
  
  CONCLUSIONS
  Multifocal IPMN of the branch ducts shows a very slow growth and evolution over time. In our study, only 3/108 patients showed mural nodules which, however, did not require any surgical procedure, indicating that careful nonoperative management may be safe and effective in asymptomatic patients.
authors.affiliation: Istituto di Radiologia, Azienda Ospedaliero Universitaria Integrata - Policlinico "G.B. Rossi", P.le L.A. Scuro 10, 37134, Verona, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Castelli
authors.forename: Davide
authors.initials: D
authors.lastname: Bosetti
authors.forename: Riccardo
authors.initials: R
authors.lastname: Negrelli
authors.forename: Valerio
authors.initials: V
authors.lastname: Di Paola
authors.forename: Lisa
authors.initials: L
authors.lastname: Zantedeschi
authors.forename: Anna
authors.initials: A
authors.lastname: Ventriglia
authors.forename: Riccardo
authors.initials: R
authors.lastname: Manfredi
authors.forename: Roberto Pozzi
authors.initials: RP
authors.lastname: Mucelli
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000231:Adenocarcinoma, Papillary / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology*; D049448:Cholangiopancreatography, Magnetic Resonance; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D008875:Middle Aged; D009942:Organometallic Compounds; D010190:Pancreatic Neoplasms / Q000473:pathology*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine